The immunology Core is Designed to provide immunologic reagents needed in Project 1 through 4. These reagents are established: monoclonal antibodies (Mabs) to the human colorectal carcinoma (CRC) antigen (Ag) GA733 and the murine homolog mEGP. Polyclonal antibodies to these Ags will be purified on Ag immunoaffinity columns. New Mab to fragments of the GA733 Ag (derived from Project 1) will be generated. Antibodies from vaccinating (under Project 3) patients, healthy individuals and patients with ulcerative colitis, will be affinity-purified for detailed tissue binding specificity analysis. In addition, Core B will produce purified baculovirus-derived GA733 Ag and mEGP. A clinical grade batch of baculovirus-derived GA733 Ag will be produced for skin testing of patients in Project 3. All reagants will be tested for purity, identity, and immunoreactivity. The centralized services provided by experienced investigators will improve quality of the Ag and antibody preparations and save overall costs as compared to their inclusion as part of each project.